You may notice that it's earlier than usual this year, that's because Easter follows the Jewish lunar calendar and not our solar Gregorian calendar. In our calendar, it falls on the first Sunday after the first full moon on or after March 21st (the Spring, or Vernal, Equinox). That means it can fall anytime from March 22nd to April 25th.
Although it has come to be known chiefly as a Christian festival, commemorating the resurrection of Christ, the name Easter in fact stems back to Anglo-Saxon pagan mythology, and Eostre (also known as Ostara), the goddess of fertility and motherhood, friend to children, symbol of the spring (the ancient word for which was eastre) and resurrection. The Vernal Equinox (on March 20th or 21st) is the time of year when the growing days and the shrinking nights find exact balance before the days overtake, and it marks the official beginning of spring.
This is the time at which Eostre was celebrated and these roots can still be seen in Easter celebrations today. The Easter Bunny was originally a hare, Eostre's favoured animal and her attendant spirit, a traditional symbol of fertility, also associated with the moon and the dawn. The connection between hares and the spring probably comes down to the fact that, though rare now, in the spring the usually shy and elusive hares can be seen 'dancing' and 'boxing' as they chase and fight one another in their mating rituals. It was thought that it was the males that fought in this way, competing for mates, but it's been found that it's usually the female hares fighting off unwanted suitors (or perhaps testing them?)!
Eggs are fairly self-evident as a symbol of birth and new life but there is also a legend in which Eostre, for the sake of amusing the children she so loved, turned her pet bird into a hare. It then laid brightly coloured eggs which the goddess bestowed on the children as gifts. Thus arose the peculiar tradition, still followed today, of painting Easter eggs and of adults, under the guise of the Easter Bunny, hiding eggs for children to find on Easter day.
As for all the chocolate, well, that may be partially because lent is finally over, but really any excuse will do!